The present invention relates to an apparatus and a method for transmitting and receiving remote control signals and more particularly to an apparatus and a method for transmitting and receiving a plurality of remote control signals for controlling an electronic device.
A variety of remote control devices for transmitting remote control signals to control various electronic devices are known. Such remote control devices generally include an input device, such as a keypad, for allowing user input, coupled to a controller which is in turn coupled to a signal transmitting circuit. In response to a user input, the controller generates an appropriate remote control signal using look up tables, and the like, from memory and causes the signal transmitting circuit to transmit the remote control signal. The signal transmitting circuit may be designed to transmit the remote control signal in a number of different forms, including, but not limited to, an IR signal and a RF signal.
One commonly used method of sending remote control signals is to transmit the signals in IR form. Remote control devices that transmit IR signals are widely used with household electronic devices. The format of the IR signal is determined by the manufacturer for each model and many such formats are known and used. Each format specifies a set of signal characteristic, which include, but are not limited to signal duration, transmission and pause intervals, carrier frequency, pulse width and pulse modulation.
However, there are several disadvantages associated with using IR signals to control an electronic device. First, the IR signal is directional and as such requires the user to point the remote control device toward the controlled device for proper transmission performance. Also, the IR signal may have a relatively short range and is easily blocked by objects such as walls, floors, ceiling and the like, so the remote control device must generally be used in the same room in which the controlled device is located.
Also, many of the IR signal formats currently used do not have sufficient data carrying capacity to transmit all the remote control messages required for control of many modern electronic devices. For example, in addition to the conventional remote control messages associated with household electronic devices, such as ON, OFF, Channel Up, Channel Down, etc., many modern electronic devices, such as satellite receivers, may require the remote control device to send other forms of data, such as ASCII data for sending alpha-numeric characters. Many existing IR signal formats were not designed to handle such additional data and simply do not include enough capacity to carry the additional types of data.
Another method of sending remote control signals is to transmit the signals in RF form. RF signals are generally non-directional and have greater range than IR signals. RF signals may also be transmitted through objects such as walls, and the like, so that the user can use the remote control device to control a device in a separate room. This extended range and ability to transmit messages through objects are beneficial in situations where a central device, such as a set top box or a satellite receiver, provides input to a plurality of devices located throughout different rooms in a building. Also, RF signal formats generally have wider bandwidths than IR signal formats.
As such, it is desirable to be able to use RF signals to control modern electronic devices. However, devices and methods using IR signals remain popular and are widely used. In order to maintain backward compatibility, i.e., allow a remote control device to control existing devices which utilize IR signals, a remote control device should also be capable of transmitting IR signals. Therefore, it is desirable to have an apparatus and a method for easily and efficiently transmitting some combination of IR and RF signals to take advantage of the features of the two signal transmission forms.
One method of transmitting a combination of IR and RF signals is to transmit a particular remote control signal in both an IR form and a RF form. In such a method, a controller generates the appropriate signal format in response to a user keypress and applies that signal format to both the IR signal transmitter and the RF signal transmitter simultaneously. In this way, the same signal is transmitted in both IR and RF forms. However, such a method does not totally overcome the problems noted above. If the transmitted signal is based on one of the conventional IR signal formats, the signal format may not have sufficient capacity to carry all of the data that the remote control device is required to send. If the transmitted signal is based on a RF signal format, the remote control may not be backward compatible with devices that use pre-existing IR signal formats. In other words, the RF signal format, while having a larger data capacity may not be usable with some types of electronic devices.
One way of overcoming the problems associated with transmitting a single signal is to simultaneously transmit different IR and RF signals, each signal based on a respective signal format, so that the IR signal provides backward compatibility while the RF signal provides a format that can transfer more data than the IR signal. However, such a method is difficult to implement from a cost standpoint. In order to implement this method, the computing power of the controller must be increased so that the controller can simultaneously process, generate and apply the two types of signal formats to both the IR and RF signal transmitters each time the user provides an input, for example by pressing a key. Such an increase in computing power requires a larger, more expensive controller which may raise the overall cost of the remote control device to unacceptable levels.
Therefore, what is required is an apparatus and a method for efficiently and cost effectively transmitting and/or receiving a combination of IR and RF signal formats each time a remote control message is required to be transmitted and/or received. The present invention involves an apparatus and method which efficiently and cost effectively transmits and/or receives a combination of IR and RF signals by transmitting and/or receives the signal in a time multiplexed arrangement.
In accordance with one aspect of the present invention, a remote control apparatus is provided having an input device for receiving remote control messages from a user, an IR signal transmitter, a RF signal transmitter, and a controller operatively coupled to the input device, the IR signal transmitter and the RF signal transmitter, the controller generating an IR signal and causing the IR signal transmitter to transmit the IR signal, and generating a RF signal and causing the RF signal transmitter to transmit the RF signal in a multiplexed manner in response to a user input.
In accordance with another aspect of the present invention, the controller of the remote control apparatus causes the IR signal transmitter to transmit the IR signal during predetermined intervals interrupted by predetermined pause periods, and causes the RF signal transmitter to transmit the RF signal during the predetermined pause periods.
In accordance with another aspect of the present invention, the controller of the remote control apparatus causes the IR signal transmitter to transmit the IR signal during predetermined intervals interrupted by predetermined pause periods, the duration of the predetermined pause period determined by the duration of transmission of the RF signal, and the controller causes the RF signal transmitter to transmit the RF signal during the predetermined pause periods.
In accordance with another aspect of the present invention, a remote control apparatus is provided comprising a first signal receiver adapted to receive a first remote control message formatted in accordance with a first signal format; a second signal receiver adapted to receive a second remote control message formatted in accordance with a second signal format, the second remote control message time-multiplexed with the first remote control message, and a controller operatively coupled to the first and second signal receivers, the controller decoding and processing the first remote control message in accordance with the first signal format upon receiving the first remote control message, and decoding and processing the second remote control message in accordance with the second signal format upon receiving the second remote control message.
In accordance with another aspect of the present invention, a method of transmitting IR and RF signals is provided comprising the steps of receiving a remote control command, and, in time multiplexed manner, generating an IR signal corresponding to the user input and transmitting the IR signal, and generating a RF signal corresponding to the user input and transmitting the RF signal.